Podcast
Questions and Answers
What effect does increasing pressure have on a system at equilibrium?
What effect does increasing pressure have on a system at equilibrium?
- Shifts equilibrium to the side with more molecules.
- Increases the rate at which equilibrium is reached.
- Shifts equilibrium to the side with fewer molecules. (correct)
- Has no effect on the position of equilibrium.
A catalyst changes the position of the equilibrium in a reversible reaction.
A catalyst changes the position of the equilibrium in a reversible reaction.
False (B)
What is the key characteristic of a catalyst that remains unchanged during a chemical reaction?
What is the key characteristic of a catalyst that remains unchanged during a chemical reaction?
It does not undergo any permanent changes.
In heterogeneous catalysis, reaction molecules are _________ onto the surface of the catalyst.
In heterogeneous catalysis, reaction molecules are _________ onto the surface of the catalyst.
Match the following catalysts with their respective applications:
Match the following catalysts with their respective applications:
According to the Maxwell-Boltzmann distribution, how does a catalyst affect the activation energy?
According to the Maxwell-Boltzmann distribution, how does a catalyst affect the activation energy?
At a dynamic equilibrium, the concentration of reactants and products are constantly changing.
At a dynamic equilibrium, the concentration of reactants and products are constantly changing.
State Le Chatelier's principle in a sentence
State Le Chatelier's principle in a sentence
When testing temperature effects on a reaction, cobalt chloride is dissolved in water, then a few drops of ________ are added to the boiling tube before investigation in a cold bath.
When testing temperature effects on a reaction, cobalt chloride is dissolved in water, then a few drops of ________ are added to the boiling tube before investigation in a cold bath.
When adding ammonium hydroxide (NHâ‚„OH) to a solution of yellow potassium chromate (Kâ‚‚CrOâ‚„) with sulfuric acid, what color change will occur?
When adding ammonium hydroxide (NHâ‚„OH) to a solution of yellow potassium chromate (Kâ‚‚CrOâ‚„) with sulfuric acid, what color change will occur?
Flashcards
Catalyst
Catalyst
A substance that increases the rate of a reaction without permanent change.
Homogeneous Catalyst
Homogeneous Catalyst
A catalyst that is in the same physical state as the reactants.
Heterogeneous Catalyst
Heterogeneous Catalyst
A catalyst that is in a different physical state than the reactants.
Activation Energy
Activation Energy
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Maxwell-Boltzmann Distribution
Maxwell-Boltzmann Distribution
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Dynamic Equilibrium
Dynamic Equilibrium
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Le Chatelier's Principle
Le Chatelier's Principle
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Pressure and Equilibrium
Pressure and Equilibrium
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Catalyst and Reaction Pathway
Catalyst and Reaction Pathway
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Effects of Temperature on Reaction Rate
Effects of Temperature on Reaction Rate
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Study Notes
Experimental Setup
- Boiling water bath set up for heating.
- Boiling tube transferred to it.
- Boiling tube moved back to cold water.
- Starting color: blue.
Catalysis and Equilibrium
- Increasing pressure shifts equilibrium to the side with fewer moles of gas to reduce pressure.
- Catalysts do not change equilibrium position, but instead increase reaction rate.
Catalysts
- Catalyst increases reaction rate without being consumed.
- May react with reactants to form intermediates.
- Provides an alternative pathway with lower activation energy.
Types of Catalysts
- Homogeneous catalyst: Same physical state as reactants (e.g., Cl radicals in ozone depletion).
- Heterogeneous catalyst: Different physical state (e.g., reactions on a surface).
- Reactants adsorb (weakly bind) to the catalyst surface.
- Reaction occurs on the surface.
- Products desorb (leave the surface).
Examples of Heterogeneous Catalysis
- Iron in the Haber process.
- Pt or Rh in reforming.
- Ni in alkene hydrogenation.
- Vâ‚‚Oâ‚… in sulfuric acid production.
Maxwell-Boltzmann Distribution
- Catalyst effect: Lower activation energy, allowing more molecules to react at a given temperature. Total molecules unchanged. Distribution shape remains similar.
- Without Catalyst:
- Curve starts from zero energy.
- Area under the curve = total number of molecules.
- No maximum molecule energy (curve doesn't hit the x-axis).
- Higher temperatures:
- More molecules exceed activation energy.
- Increased collision rate leads to faster reactions.
- Higher molecular kinetic energy meaning more collisions.
Dynamic Equilibrium & Le Chatelier's Principle
- Dynamic equilibrium: Forward and reverse reaction rates are equal. Reactant and product concentrations remain constant.
- Le Chatelier's principle: Equilibrium shifts to counteract changes.
- More product formation shifts equilibrium to the right.
- More reactant formation shifts equilibrium to the left.
Experimental Procedures - Investigating Concentration Changes
- Starting with yellow Kâ‚‚CrOâ‚„ solution + dilute Hâ‚‚SOâ‚„.
- Result: Orange solution.
- Adding NHâ‚„OH turns it back to yellow.
Experimental Procedures - Investigating Temperature Effects
- Cobalt chloride dissolved in water.
- A few drops of HCl added.
- Observing color change in a boiling tube placed in an ice bath.
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